Resistance Genes to Fight Against Soybean Diseases and Pests
Department of Crop Sciences and
Research Plant Pathologist with the
USDA-Agricultural Research Service
Management of soybean diseases and pests involves many approaches including cultural aspects like crop rotation, tillage practices and cultivar or variety selection. Other management practices include pesticide applications of fungicides or insecticides to the surface of seed or on plant foliage for protection from disease and pest organisms. One of the most common management practices is to select resistant soybean varieties. The resistance in these varieties is an accumulation of many years of research that includes the discovery and characterization of the resistance, and its incorporation into commercially adapted varieties. One research priority in the Laboratory for Soybean Disease Research (http://www.soydiseases.illinois.edu) is to discover, characterize, and map novel disease and pest resistance genes. Soybean accessions from the United States Department of Agriculture-Agricultural Research Service (USDA-ARS) Soybean Germplasm Collection at Urbana, IL have been used extensively for discovering new sources of resistance. One example is the discovery of soybean aphid resistance. When the soybean aphid arrived as a new pest to the Midwest in 2000, commercial soybean varieties with aphid resistance were not available and sources of aphid resistance in the soybean collection were not known. Initial studies challenged many soybean accessions from the collection under controlled greenhouse conditions to find sources of resistance. Currently, the inheritance, resistance expression, map location, and genetic relationships of resistance genes have been published. Public and private soybean breeders are utilizing the available genetic information on the resistance genes and lines containing them to develop new soybean aphid resistant varieties. Another example includes the discovery of many potentially new sources of resistance to soybean rust. Prior to the first report of soybean rust in the continental U.S. in 2004, most of the soybean germplasm collection had been evaluated for resistance in a secure containment facility at Fort Detrick, Maryland, and over 800 accessions were short-listed as potential resistance sources. Useful genes from these sources are being characterized and added to adapted soybean varieties. In addition to the discovery of new sources of resistance, current soybean cultivars or pre-commercial lines are being evaluated through the Varietal Information Program for Soybeans (VIPS) for resistance to Phytophthora root rot, Sclerotinia stem rot, soybean aphid, soybean mosaic virus, and sudden death syndrome as an additional service to growers and seed companies. This program provides information to help soybean growers select soybean varieties for production.